1. Field of the Invention
The present invention relates to a transport vehicle and a transport vehicle system.
2. Description of the Related Art
An overhead traveling vehicle system has been used for transport in a clean room or the like. JP2012-162096A describes that a branching portion and a merging portion are provided on a traveling route. JP2012-40961A describes that traveling routes for an overhead traveling vehicle are made to cross each other longitudinally and transversely. However, in JP2012-40961A, since a rail is mechanically rotated in a crossing portion of the cross, the overhead traveling vehicle cannot autonomously change a traveling direction.
When the transport vehicle is enabled to travel while autonomously changing directions of longitudinal and transverse paths, it is possible to provide a large number of crossing portion of the cross of the paths. This allows dense arrangement of the paths, and also allows free layout of the path. Hence the transport vehicle has more options for traveling routes, and can select a traveling route so as to detour around a congested portion and the like and reach a destination via a short distance. Further, when an opening is provided at the center of the path with treads provided on both sides of the opening, and a transport is supported by a column passing through the opening, it is possible to realize a suspension type transport vehicle and exchange an article with a location immediately below the path.
However, this requires a mechanism in which the transport vehicle can safely travel through the opening formed in the crossing portion of the paths, and the transport vehicle autonomously and reliably switches between longitudinal traveling and transverse traveling.